Continue a screening program to find patients with agglutinating cytotoxic or platelet complement fixing histocompatibility antibodies. Plasmapherese selected patients to obtain 250 ml or greater quantities of monospecific and duospecific sera totaling three liters to be deposited in the Transplantation and Immunology Branch, NIAID Serum Bank during the contract year, following a list of desired HL-A specificities provided by the Project Officer, which will be based on the specificities available in the department of Immuno-hematology University hospital Leyden, and to provide an additional two liters of possible new specificity sera in 250 ml or greater quantities for deposit in the Transplantation and Immunology Branch, NIAID Serum Bank during the contract year. Conduct the necessary typing studies required to achieve the above specifications.